Separation of Isotactic and Syndiotactic Poly(methyl methacrylate) by a Competitive Adsorption Method

Miyamoto, Takeaki; Tomoshige, Shozo; Inagaki, Hiroshi

doi:10.1295/polymj.6.564

Cited by 24 publications

(4 citation statements)

References 13 publications

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“…So far, there are a limited number of reports − describing chromatographic separation of stereoregular polymers according to their stereochemical structures. For example, Miyamoto et al attempted to separate the mixtures of highly isotactic (it-) and highly syndiotactic (st-) poly(methyl methacrylate)s (PMMAs) by both thin-layer chromatography 2 and competitive adsorption method 3 .…”

Section: Introductionmentioning

confidence: 99%

Discrimination of Poly(ethyl methacrylate)s According to Their Molar Mass and Tacticity by Coupling Size Exclusion Chromatography and Liquid Chromatography at the Critical Adsorption Point

et al. 2000

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A coupling of size exclusion chromatography (SEC) and liquid chromatography at the critical adsorption point (LC CAP) has been applied to simultaneous discrimination of stereoregular poly(ethyl methacrylate)s (PEMAs) according to their molar mass and tacticity. The two-dimensional SEC/LC CAP separations were carried out with a chromatographic system which consisted of two analytical columns, one SEC column (polystyrene/divinylbenzene gel) and one LC CAP column (aminopropyl bonded silica gel) connected in series. Narrow fractions of PEMA samples eluted from the SEC column were on-line forwarded into the LC CAP column to be separated according to their tacticity. The column system was flushed with tetrahydrofuran (THF)/cyclohexane mixed eluents at compositions of 64/36 and 56/44 w/w, to attain the molar-mass-independent elution of either highly syndiotactic or highly isotactic PEMAs, respectively. In these eluents, the SEC column still separated PEMAs solely according to their molar masses, while the LC CAP column system discriminated PEMAs according to their tacticity. By use of the coupled SEC/LC CAP technique, the influence of molar mass distribution of analyzed sample on its separation according to tacticity in the LC CAP column was suppressed. For the first time the separation of stereoregular polymers over the entire tacticity range has been demonstrated.

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Section: Introductionmentioning

confidence: 99%

Discrimination of Poly(ethyl methacrylate)s According to Their Molar Mass and Tacticity by Coupling Size Exclusion Chromatography and Liquid Chromatography at the Critical Adsorption Point

et al. 2000

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“…The presence of CH 3 0MgC1 may be one of the factors causing the coexistence of isotactic-ftavoring and syndiotactic-favoring propagating species. Regarding this problem, we are now examining the chemical structures 29 of syndiotactic P(MMAd8) and isotactic P(MMA-d 8 ) obtained by the polymerization with C 4 H 9 MgCl followed by fractionation using the competitive adsorbtion method, 30 and we are also studying the effects of ether 31 and BIPK on the polymerization. The results will be published in the near future.…”

Section: Och3mentioning

confidence: 99%

Studies on the Polymerization of Methyl Methacrylate with Butylmagnesium Chloride by the Aid of Totally Deuterated Monomer—Structures of Polymerization Products and Fate of Initiator

Ute

Kitayama

Hatäda

1986

Polym J

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ABSTRACT:Totally deuterated methyl methacrylate (MMA-d8) was polymerized by C4 H 9 MgCl in toluene at -78"C, and the resulting polymer and oligomer were analyzed by 1 H NMR spectroscopy. The polymer and oligomer was found to contain butyl pentadeuteroisopropenyl ketone (BJPK-d5) units. The ketone was formed by the addition of the initiator onto the carbonyl group of the monomer. The content of BIPK-d5 units in the polymer and oligomer was found to be 0.3 and 0.4 per chain, respectively. FD-and EI-mass spectra of the fractionated oligo(MMA)s indicated that most of the BIPK units were located at their terminating chain ends. Structures which were produced by intramolecular cyclization and by carbonyl addition of propagating anions onto MMA or BIPK were found at the end of the oligomer chain, but the amounts of these structures were at most I 0% of the chain. The fate of the initiator during the polymerization was clarified for the most part. From the results, the mechanism of polymerization is discussed in some detail.

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“…Stereoblock PMMAs that consist of it - and st -PMMA blocks connected in one linear chain have been prepared via various approaches. Although there have been several reports on the formation of it - b - st -stereoblock PMMAs via anionic polymerization under certain conditions since the 1950s, they are mostly mixtures of it - and st -PMMAs or are randomly segmented it - and st -PMMA blocks with uncontrolled block lengths and broad molecular weight distributions (MWDs) [3,40,41,42,43,44,45,46,47,48,49]. The well-defined it - b - st -stereoblock PMMA was first synthesized in 1986 via a sequential living anionic block copolymerization of two monomers, diphenylmethyl and triphenylmethyl methacrylates, which resulted in syndiotactic ( rr = 84%) and isotactic ( mm = 91%) sequences, respectively, followed by hydrolysis and methylation of their ester moieties [22].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Isotactic-block-Syndiotactic Poly(methyl Methacrylate) via Stereospecific Living Anionic Polymerizations in Combination with Metal-Halogen Exchange, Halogenation, and Click Reactions

2017

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Isotactic (it-) and syndiotactic (st-) poly(methyl methacrylate)s (PMMAs) form unique crystalline stereocomplexes, which are attractive from both fundamental and application viewpoints. This study is directed at the efficient synthesis of it-and st-stereoblock (it-b-st-) PMMAs via stereospecific living anionic polymerizations in combination with metal-halogen exchange, halogenation, and click reactions. The azide-capped it-PMMA was prepared by living anionic polymerization of MMA, which was initiated with t-BuMgBr in toluene at -78 • C, and was followed by termination using CCl 4 as the halogenating agent in the presence of a strong Lewis base and subsequent azidation with NaN 3 . The alkyne-capped st-PMMA was obtained by living anionic polymerization of MMA, which was initiated via an in situ metal-halogen exchange reaction between 1,1-diphenylhexyl lithium and an α-bromoester bearing a pendent silyl-protected alkyne group. Finally, copper-catalyzed azide-alkyne cycloaddition (CuAAC) between these complimentary pairs of polymers resulted in a high yield of it-b-st-PMMAs, with controlled molecular weights and narrow molecular weight distributions. The stereocomplexation was evaluated in CH 3 CN and was affected by the block lengths and ratios.

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Separation of Isotactic and Syndiotactic Poly(methyl methacrylate) by a Competitive Adsorption Method

Cited by 24 publications

References 13 publications

Discrimination of Poly(ethyl methacrylate)s According to Their Molar Mass and Tacticity by Coupling Size Exclusion Chromatography and Liquid Chromatography at the Critical Adsorption Point

Discrimination of Poly(ethyl methacrylate)s According to Their Molar Mass and Tacticity by Coupling Size Exclusion Chromatography and Liquid Chromatography at the Critical Adsorption Point

Studies on the Polymerization of Methyl Methacrylate with Butylmagnesium Chloride by the Aid of Totally Deuterated Monomer—Structures of Polymerization Products and Fate of Initiator

Synthesis of Isotactic-block-Syndiotactic Poly(methyl Methacrylate) via Stereospecific Living Anionic Polymerizations in Combination with Metal-Halogen Exchange, Halogenation, and Click Reactions

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